1. Field of the Invention
The present invention relates to a communication apparatus to which other communication terminals can be connected.
2. Related Background Art
In Japanese Patent Publication No. 62-16595 or the like, there has been disclosed a button telephone system in which an existing other terminal such as a facsimile apparatus or the like is connected to a button telephone set which transmits and receives a speech signal and a data signal to and from an exchange through different lines. According to the system of Japanese Patent Publication No. 62-16595, the exchange transmits a connection request to the facsimile apparatus to the button telephone set to which the facsimile apparatus is connected.
However, in the above conventional system (Japanese Patent Publication No. 62-16595), when a speech signal line is switched from the button telephone set to the other existing terminal (facsimile apparatus), the speech line is switched to the terminal side by a control circuit of the button telephone set which received a data signal from the exchange side. Therefore, the exchange side must detect whether a distant side to be connected to the button telephone system is a telephone set or a facsimile terminal. Further, when the distant side to be connected to the button telephone system has been determined to be a facsimile apparatus, a control circuit, a control program, and the like to transmit switching instruction data of a communication signal line to the button telephone set are needed. As mentioned above, the system of Japanese Patent Publication No. 62-16595 has a problem in that the control means on the exchange side becomes complicated and increases.
Further, in the conventional system, since an instruction to switch is performed on the exchange side, there is a problem in the operation in that the operator cannot manually switch the speech line to the terminal side at an arbitrary time point.
On the other hand, in a conventional button telephone system having a facsimile apparatus therein, when the facsimile apparatus is enclosed in the extension, by assigning the facsimile apparatus to one line of the extension and by providing special control means in a main unit, the facsimile apparatus is enclosed in the extension. Or, control means only for use of the facsimile apparatus is provided to the outside of the main unit by an adapter type or the like, thereby enclosing the facsimile apparatus to the extension. In these button telephone systems, the special control means detects and controls an originating call request, a dial signal, etc. from the facsimile apparatus, thereby enabling the facsimile apparatus to execute a predetermined communication.
In the conventional button telephone systems mentioned above, there is a problem in that a special extension needs to be assigned to one line in order to enclose the facsimile apparatus or the like and the button telephone set cannot be connected to the extension nor used.
Further, in the case of the construction in which special control means is provided in the main unit, there is a problem in that the control means of the main unit becomes complicated and increases.
Or, in the case of providing the control means of the adapter type to the outside of the main unit, there are problems such that an installing space of the adapter is needed and the manufacturing cost rises due to a casing for an adapter or the like.